Dietary cholesterol or egg intake and cardiovascular disease and mortality

Introduction

Cholesterol is a common nutrient in the human diet, and eggs are a major source of dietary cholesterol. However, despite decades of research, the association between dietary cholesterol intake and cardiovascular disease and mortality remains controversial.

Results

This study followed 29,615 adults (mean age 51.6 years, 44.9% men, 31.1% Black) from six prospective cohort studies in the United States for a mean follow-up of 17.5 years, during which 5,400 cardiovascular disease events and 6,132 all-cause deaths occurred.

The results showed that a daily intake of 300 mg of dietary cholesterol was significantly associated with a higher risk of cardiovascular disease and all-cause mortality, and each additional half an egg consumed daily was significantly associated with a higher risk of cardiovascular disease and all-cause mortality. After adjusting for dietary cholesterol intake, the association between egg intake and cardiovascular disease and all-cause mortality was no longer significant.

Relationship between Dietary Cholesterol Intake and Cardiovascular Disease and All-Cause Mortality

Relationship between Egg Consumption and Cardiovascular Disease and All-Cause Mortality

Relationship between Each Additional Half Egg Per Day and Cardiovascular Disease and All-Cause Mortality

Discussion

As a major source of dietary cholesterol, egg consumption exhibits differential associations with coronary heart disease, stroke, heart failure, and mortality. A recent meta-analysis showed that compared with infrequent egg consumption (typically <1 egg per week or never), frequent egg consumption (typically ≥1 egg per day) was associated with a significantly increased risk of heart failure and a significantly reduced risk of stroke. However, there was no significant association with stroke mortality or all-cause mortality, and no significant association with coronary heart disease was reported. Another meta-analysis, examining all cardiovascular disease subtypes, reported a significant positive dose-response relationship between egg consumption and cardiovascular disease.

The current study found a significant association between dietary cholesterol intake and cardiovascular disease incidence and all-cause mortality, independent of fat content and diet quality. These findings are consistent with evidence that reduced dietary cholesterol intake and the replacement of saturated fat with saturated, such as unsaturated, fats significantly reduce total cholesterol (primarily LDL cholesterol) concentrations. Furthermore, the cholesterol content of eggs fully explained the significant association between egg consumption and cardiovascular disease, and it also largely explained the significant association between egg consumption and all-cause mortality, providing additional support for the significant associations between dietary cholesterol intake and obesity, cardiovascular disease, and all-cause mortality. Although the associations between dietary cholesterol intake and cardiovascular disease and all-cause mortality were no longer significant after accounting for egg, unprocessed red meat, and processed meat intake, it remains unclear whether the cholesterol in these foods is more harmful than other cholesterol-containing foods. Furthermore, since egg intake contributes 25% of total dietary cholesterol and meat intake contributes 42%, changes in dietary cholesterol intake from other foods may not be statistically sufficient to substantially alter this association. Mechanistically, eggs and processed or unprocessed red meat are rich in other nutrients, such as choline, iron, carnitine, and added sodium (in processed meat), which also contribute to cardiovascular disease risk through different pathways. Therefore, the study suggests that people need to reduce their cholesterol and egg yolk intake in their diet and follow the Institute of Medicine's recommendations for a healthier diet.

anna@hihealthbio.com